Field of the Invention
The present invention is drawn to oilfield drilling structures which may be easily moved from one drilling position to another by use of outboard, hinged outriggers. These structures are useful in drilling oil wells in fields where a great many boreholes are required to sustain the production of oil. The invention further provides a drill rig having features which allow it to be transported along roadways from one oilfield drilling location to another.
Description of the Related Art
There are numerous patents and publication regarding ‘mobile’ oil well drilling rigs that may be transported in a ‘stowed’ mode along public highways and which may also be moved in an ‘erected’ mode when drilling multiple adjacent wells within a particular oil field. One such patent, U.S. Pat. No. 3,754,361, incorporated by reference herein for all it discloses, discussed a wheeled structure to transport a drilling rig with rotatable wheel assemblies which allow the rig to be moved by using a ‘fifth wheel’ arrangement which may be rotated to any angle. These wheels are permanently attached, however, which may consume considerable space and add unnecessary weight.
U.S. Pat. No. 4,375,892 discloses a more flexible ‘dolly type’ structure which also allows a rig to be moved in any desired direction. However, this structure shares many of the same general problems as U.S. Pat. No. 3,754,361, as described above.
Furthermore, U.S. Pat. Nos. 4,305,237; 4,290,495; 3,807,109; 4,823,953; 4,823,870 and US Publication number 2007/0215359 all show various arrangements for movable drill rigs.